Voice user interfaces are widespread and used to control various computing devices, such as smartphones, car entertainment systems, TV sets, game consoles, wearables, and so forth. There are devices for which the voice user interface is the most convenient form of user input. In some situations, the voice user interface is the only form of user input. To provide security for a computing device (and user), a secure, imposter-proof voice authentication is needed.
Current authentication methods tend to be inaccurate and susceptible to man-in-the-middle attacks. For example, an imposter could simply record the user's voice and play it back to deceive the voice authentication system (often referred to as “playback spoofing attack”). Existing methods for detecting the playback spoofing attacks are neither reliable nor stable, especially if a spoken password is short or voice authentication is performed in a noisy environment.